Scientific Reviews: Two-Detector System for Small-Angle Neutron Scattering Instrument

Most of the objects of small-angle neutron scattering (SANS) experiments require the measurements of a studied sample in a wide range of momentum transfer (Q-range). Larger Q-range means more reliable determination of a model of the investigated material as well as higher accuracy of its calculated structural parameters. The dynamic range of SANS instruments is normally determined by the size of the detector, which is limited mainly by technical reasons and by the wavelength range of available thermal neutrons in the neutron beam. Even in the case of the largest detector (1 m2) at one of the best beam lines—the D22 instrument at ILL—the dynamic range is about 50. Usually the problem of the Qrange is solved by a sequence of measurements with the detector at different positions. However, it leads to considerable increase in the data acquisition time. Moreover, the problem becomes critical when it is necessary to study processes in real time, especially irreversible processes.